Slow Cooking Thursday – Pumpkin Butter

First you need pumpkin or squash puree. You really want to start with fresh puree, and not use the canned puree. It really makes a difference in the taste. And let me tell you, butternut squash is super tasty as a “butter”… I like to start with about 5 quarts of puree and other ingredients, so I can use my 6 quart crock and make a big batch. A pumpkin yield is usually about 2 or 3 cups of puree per 6 inch diameter pie pumpkin. That cooks down to about half that volume in making pumpkin butter. You can steam or roast (I think roasting brings more sweetness out in the pumpkin) your pumpkin then puree with a blender or immersion blender until smooth.

Put the cover on the slow cooker sideways to vent. You don’t want to seal the crock tightly because the steam needs to escape so the pumpkin butter can reduce in volume and thicken.

Leave to cook for 6 – 8 hours. How long depends on the size and power of your crockpot, how much water your pumpkin started with, how thick you like your butter. Stir the pumpkin butter occasionally.

When the pumpkin butter has reduced in volume by about half, taste it to check the sweetness. Add more maple syrup to taste, if needed. If you left it a bit too long and it is too think for your taste, mix in a bit of apple cider to thin.

Allow pumpkin butter to cool, divide into pint sized freezer safe containers and freeze, putting one in the refrigerator to enjoy right away.

Why freeze pumpkin butter instead of canning?: The reason I freeze pumpkin butter instead of canning is that pumpkin and squashes are not a veggie recommended for home canning, even with a pressure canner. According to the According to The National Center for Home Food Preservation (a land-grant university consortium sponsored by the USDA, and considered to be the leading authorities on food safety science and food preservation research):

“Home canning is not recommended for pumpkin butter or any mashed or pureed pumpkin or winter squash, but we do have directions for canning cubed pumpkin. Pumpkin puree can be frozen or made into a spicy pumpkin leather…

There are not sufficient data available to allow establishing safe processing times for any of these types of products. It is true that previous USDA recommendations had directions for canning mashed winter squash, but USDA withdrew those recommendations…

Some of the factors that are critical to the safety of canned pumpkin products are the viscosity (thickness), the acidity and the water activity. Studies conducted at the University of Minnesota in the 1970’s indicated that there was too much variation in viscosity among different batches of prepared pumpkin purees to permit calculation of a single processing recommendation that would cover the potential variation among products (Zottola et. al, 1978). Pumpkin and winter squash are also low-acid foods (pH > 4.6) capable of supporting the growth of Clostridium botulinum bacteria which can cause the very serious illness, botulism, under the right storage conditions. If the bacteria are present and survive processing, and the product has a high enough water activity, they can thrive and produce toxin in the product.

More recent research with pumpkin butter has been done at the University of Missouri. Pumpkin butter is mashed or pureed pumpkin that has had large quantities of sugar added to it, but not always enough to inhibit pathogens. Sometimes an ingredient such as vinegar or lemon juice is added to the formulation to increase the acidity (decrease the pH). However, pumpkin butters produced by home canners and small commercial processors in Missouri have had pH values as high as 5.4. In fact, the pH values seemed to be extremely variable between batches made by the same formulation (Holt, 1995).

It is not possible at this point to evaluate a recipe for pumpkin or mashed squash for canning potential by looking at it. At this point, research seems to indicate variability of the products is great, and in several ways that raise safety concerns. It is best to freeze pumpkin butters or mashed squash.”

So, then, pumpkin pie filling, pureed pumpkin, and pumpkin butter would NOT be candidates for safe home canning. Yes, I know you can find old recipes and text books to find processing times, but, dude, just be safe and freeze your butter in containers and store the opened one in the fridge. Better safe than sorry!!

One response to “Slow Cooking Thursday – Pumpkin Butter”

Pumpkin butter is one of my absolute seasonal favorites, and I had no idea – none – that it was possible to get it without buying it in the store. Seems so silly an obvious now, but wow, how surprising I could make my own!